The development of nature reserves in China has entered a new stage of quality-benefit model from the quantitative expansion. Based on the logistic model and R language, this paper estimated the upper limit of development of nature reserves by using the statistical yearbook data of nature reserves. At the same time, the curvature derivative method of high data curve was used to divide the development stage, and to measure the continuous growth and growth rate. The results show that:(1) the theoretical saturation value of the area was 15470.00 million hectares. (2) The development process of the nature reserves was divided into slow beginning period (1956-1989), rapid development period (1990-2008), and stable improvement period (2009-now). (3) At present, it is in a stable and improvement period. The area of nature reserves has been gradually saturated. The number is still increasing slightly. We hoped that our results of this study can provide a reference for the competent authorities of nature reserves to formulate management policies and plans and integrate the establishment of a nature reserve system with the national parks as the main body.